Subtract 21/20 from 12/63, Solve 12/63

Subtract 21/20 from 12/63

1^st number: 12/63, 2^nd number: 1 1/20

12/63 - 21/20 is -361/420.

Find the least common denominator or LCM of the two denominators:
LCM of 63 and 20 is 1260

Next, find the equivalent fraction of both fractional numbers with denominator 1260
For the 1st fraction, since 63 × 20 = 1260,
12/63 = 12 × 20/63 × 20 = 240/1260
Likewise, for the 2nd fraction, since 20 × 63 = 1260,
21/20 = 21 × 63/20 × 63 = 1323/1260
Subtract the two like fractions:
240/1260 - 1323/1260 = 240 - 1323/1260 = -1083/1260
After reducing the fraction, the answer is -361/420

MathStep (Works offline)

Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad